Study of pyrolysis product distribution characteristics of lignite in the context of electrochemical catalytic gasification

Abstract

To support the effective utilization of lignite, which is abundant throughout China, and the problems associated with the existing common catalytic methods, electrochemical catalytic coal gasification (ECG) is proposed. As an important process in ECG, electrochemical catalytic pyrolysis (ECP) was studied. ECP experiments were performed on Fuxin coal. The influence of temperature and power (thermal electrons) on the generation of various pyrolysis products was studied. Char and tar production decreased as the temperature and power were increased. However, gaseous production increased with an increase in temperature and power. The thermal evolution and graphitization degree of coal char were increased as the temperature and power were increased. However, the degree of crystallite structure ordering of char and thermal evolution of coal char were still lower in ECP than in common coal pyrolysis (CCP). Unlike temperature, an increase in power increased the fractions of aliphatic and monocyclic aromatic compounds but decreased the fraction of fused-ring compounds. The proportions of CO and H₂ in the gaseous products increased with temperature; those of other components decreased. However, the proportion of CO₂ decreased with an increase in power, whereas the other components increased. Compared with CCP, ECP was more conducive to the full pyrolysis of coal and the formation of gaseous products. More aliphatic compounds and monocyclic compounds were present in tar produced by ECP than CCP; these were all beneficial to the subsequent gasification reaction. A deeper understanding of the action of thermal electrons on the whole ECG process would be useful.